In the past, various attempts have been made to obtain new and better anti-inflammatory agents. For the most part, these efforts have involved the synthesis and testing of various steroidal compounds such as the corticosteroids or non-steroidal substances of an acidic nature such as phenylbutazone, indomethacin and the like, including piroxicam. The latter substance is a member of a class of anti-inflammatory/analgesic N-heteroaryl-4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxides (known as oxicams) described and claimed in U.S. Pat. No. 3,591,584 and is specifically, 4-hydroxy-2-methyl-N-(2-pyridinyl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide. Other agents of this type are disclosed in U.S. Pat. Nos. 3,787,324, 3,822,258, 4,180,662 and 4,376,768, as well as in German Offenlegungsschrift No. 2,756,113 and Published European Patent Application No. 138,223. In U.S. Pat. No. 4,434,164, there are specifically described and claimed the ethylenediamine, monoethanolamine and diethanolamine salts of 4-hydroxy-2-methyl-N-(2-pyridinyl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide, which are particularly valuable in pharmaceutical dosage forms as non-steroidal therapeutic agents for the treatment of painful inflammatory conditions, such as those caused by rheumatoid arthritis, since they are all crystalline, non-hygroscopic, rapidly-dissolving solids with high water solubility. In U.S. Pat. No. 4,309,427, there are disclosed certain novel acyl derivatives (i.e., enol esters) of 4-hydroxy-2-methyl-N-(2-pyridinyl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide and 4-hydroxy-2-methyl-N-(6-methyl-2-pyridinyl)-2H-1,2-benzothiazine-3-carboxa mide 1,1-dioxide, which are useful as non-steroidal therapeutic agents for alleviating various inflammatory conditions, including those of the skin, especially when given by the topical route of administration. However, in the continuing search for still more improved anti-inflammatory/analgesic agents, there is a need for anti-arthritic agents that are orally administrable.
In this connection, it is to be noted that while the prior described enolic oxicam lower alkyl ethers of U.S. Pat. No. 3,892,740 do not possess anti-inflammatory activity to any substantial degree, the more recently described anti-inflammatory oxyalkyl ethers of the enolic oxicams of U.S. Pat. No. 4,551,452 all require that the oxyalkyl moiety be restricted to --CH.sub.2 --O--, --CH(CH.sub.3)--O-- or --CH(C.sub.6 H.sub.5)--O--. As a result, there is little or no information available about the effect of other oxyalkyl ethers in this area and particularly, about compounds like the corresponding enolic oxicam lower oxyalkyl ethers wherein the alkyl moiety is exclusively arranged in a straight chain.